Prostacyclin effect on cardiovascular system in man evaluated by echocardiography

Area of Science:

• Cardiovascular Physiology
• Pharmacology

Background:

• Prostacyclin (PGI2) is a potent vasodilator with known cardiovascular effects.
• Understanding the specific hemodynamic impacts of intravenous PGI2 in humans is crucial for its clinical application.

Purpose of the Study:

• To investigate the cardiovascular effects of a continuous intravenous infusion of prostacyclin (PGI2) in healthy human volunteers.
• To assess changes in blood pressure, heart rate, cardiac output, and vascular resistance following PGI2 administration.

Main Methods:

• Echocardiography was used to measure various cardiovascular parameters in human volunteers.
• Parameters including blood pressure, heart rate, ventricular dimensions, stroke volume index, cardiac index, and peripheral vascular resistance were recorded during PGI2 infusion and recovery.

Main Results:

• Intravenous prostacyclin (PGI2) infusion led to a significant reduction in mean blood pressure (MBP) without altering heart rate (HR).
• A decrease in peripheral vascular resistance (PVR) was observed, accompanied by an increase in cardiac index (CI) and stroke volume index (SVI).
• Left ventricle fractional shortening (FS) and ejection fraction (EF) increased, indicating reduced end-systolic diameter (ESD).

Conclusions:

• Prostacyclin (PGI2) infusion in humans at the studied rate induces hypotension, primarily due to arterial vasodilation.
• The lack of heart rate reflex response to afterload reduction suggests a potential nerve-mediated effect of PGI2.
• The absence of changes in end-diastolic diameter indicates no significant venous vasodilation occurred.